GPS MS1E
GPS receiver with uBlox GPS-MS1E
In 2006, inexpensive small GPS modules from µ-Blox with matching antennas were sold on a well-known auction platform. These are based on the SirfStar I/LX chipset. Because of the low price I ordered two of these modules.
The picture shows the front and back side of the GPS module and antenna. The GPS module needs only a few external components:
A low drop voltage regulator generates the 3.3V supply voltage. The buffer battery ensures that settings are retained. The serial interface is converted from TTL to RS232 level by a MAX3232.
I built the prototype on a breadboard:
The USB connector was first used only for power supply, but later it was extended with a USB to serial converter from a cell phone data cable. Also the memory battery is not yet connected in the picture.
Backside of the board:
Getting started
To use the receiver now, it first needs a firmware update to the latest version 1.35. To perform the update, the Normal/Update jumper is set to Update. The RS232 interface of the PC is connected to the update port. After applying the operating voltage, the µBlox software uploads the update to the receiver. Afterwards the receiver is up to date.
After switching on the receiver for the first time, it does not yet provide NMEA data, as is usual. It must first be switched from Sirf protocol to NMEA protocol with the SirfDemo software. After that it can be used like any other GPS receiver with all GPS and charting programs without any problems.